Artificial hand



(No Model.) 2 Sheets-Sheet 1. S. LUCAS.

ARTIFIOIAL HAND. No. 429,243. Patented June 3, 1890.

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SAMUEL LUCAS, OF POQUETANUCK, CONNECTICUT.

ARTIFICIAL HAN D.

SPECIFICATION forming part of Letters Patent No. 429,243, dated June 3, 1890.

Application filed March 17, 1390.

T0 aZZ 071 0121, it may concern.-

Be it known that I, SAMUEL LUCAS, a citizen of the United States, residing at Poquetanuck, in the county of New London and State of Connecticut, have invented certain new and useful Improvements in Artificial I-Iands, which improvements are fully set forth and described in the following specification, reference being had to the accompanying two sheets of drawings, in which- Figure 1 is a side View of a hand embodying my improvements, and Fig. 2 a View of the same from the back or top side. Fig. 3 is a sectional View on line 2 z of Fig. 2; and Fig. 4, a similar View of those portions adjacent to the hinge-joint, but with the spring pawl thrown out .of engagement with the ratchetteeth, as hereinafter described. Fig. 5 is a sectional view on line 00 a: of Fig. 1, and Fig. 6 is a perspective view of the thumb detached from the hand and inverted to expose the tenon or boss by means of which it is strongly connected with said hand. In'Fig. 7 I have shown the index-finger with a fork attached thereto, and in Fig. 8 an end "iew of the clamping-ferrule v, by means of which said fork or any similar tool may be attached to said finger.

The object of my invention is to provide an artificial hand that may be used to perform certain kinds of manual labor, which shall be strong and serviceable and cheaply constructed.

Referring to the drawings, the letter a denotes the body or main section of the hand, made of wood or other light material. This section a is provided with a shank b, that is fitted to enter a socket in a false wrist secured to the stump of the arm in any of the ways common to this class of devices.

So'far as I am familiar with the methods of securing artificial hands to the stump it has been a common practice to provide a shank substantially like my shank b in outward appearance, but fastened rigidly in the hand-section. In the hand here shown the said shank is pivotally secured in a recess in said hand by a screw or pin 0, as shown in Figs. 3 and 5, and is held normally in alignment with the hand by a bow-spring cl, made of fiat spring metal, whose free ends support Serial No. 344,088. (No model.)

the shank b on either side. This construction relieves the rigidity which otherwise would result and prevents any sudden and painful shock to the natural stump of the wearer. hen lateral pressure is brought to bear on the artificial hand, the spring d may yield, as shown in dotted lines in Fig. 5; but said spring is of sufficient strength to return the hand to its normal position when such pressure is removed.

Section a is slotted to receive a set of artificial fingers e, that are hinged in place by a rod or pintle f, extending through the entire series, and each of said fingers is formed at its inner or hinge end with ratchet-teeth that are preferably concentric with the pintle f. A spring-pawl h is provided to operate with each finger, said pawl being screwed to the back side of section a, and preferably formed of a single piece of slitted sheet metal, as shown. hen one or all of the fingers are swung on their hinges, as in the act of closing the fingers, the described spring-pawls drop in the rear of the ratchet-teeth and hold said fingers firmly in the positions to which they have been adjusted until the pawls are raised, which is accomplished through and by means of a flattened bar 2', that lies in a channel in section a under the pawls h and near the free ends of said pawls. One end of this bar 1' is bent at a right angle to form an operatinghandle 7s. hen it is desired to raise the pawls h from the ratchet-teeth, it is only necessary to depress the operating-handle k and thus rock bard into the position shown in Fig. 4, when the pawls are all raised and the fingers may be returned to their extended position. A guard-plate m may be provided to protect the operating-handle 7c, and also to limit its downward movement, although such a plate is not absolutely necessary.

In connection with each finger I provide a spring '17, for automatically returning the fingers to their extended position when the pawls are raised. These springs, as here illustrated, consist of rubber bands or strips having one end fastened by screw 0 to the back of the hand and the other end or loop attached to a wire eye q,secured to the finger. IVhen the pawls h are disengaged from the ratchetteeth, these springs 02. immediately contract and draw the fingers back to their extended position. Springs of wire could be substituted for the described rubber bands, if desired; but I find the latter cheap and effective and easily replaced when worn out or broken.

The thumb rof my artificial hand is hinged to the side of section aby a screw 5, and while allowed to move freely on the pivot thus pro vided is limited in such movement by a projecting portion 3, that may abut a corresponding projection ton section a, as best shown in Fig. 1. To insure great strength to thumb r, I have provided on it a boss or tenon 2', that is concentric with the pivot-screw s and enters a eorres 'ionding mortise in section a.

The first and second joints of the several fingers of my artificial hand are intentionally partially closed at all times and are so constructed for the following reason: \Vhen said fingers are swung around toward the palm of the hand, they then form a hook (see Fig. of great strength, by means of which various things may be lifted-as, for example, the hail of a pail or of a coal-hod-whereas it said first and second joints were in line wit-h the ratchet-joints so perfect a hook could not be formed.

Various tools may be attached to the fingers, one of which-a forkis illustrated in Fig. 7. Said fork is provided with two ferrules through which the finger passes, one of which v is formed of two overlapping plates of spring metal, (shown most clearly in Fig. 8,) that clasp the finger firmly and prevent the accidental displacement of the fork.

My artificial hand as a whole is strong and serviceable, is not expensive to make, and

enables one crippled by loss of a hand to perform many duties otherwise impossible.

Having described my invention, I clain1 1. In combination with a palm having hinged thereto aseries of fingers with ratchettceth, a corresponding series of spring-pawls, as set forth, and a corresponding series of springs connecting the said palm and fingers, sul'istantially as and for the purpose specified.

2. In an artificial hand formed, essentially, of a series of hinged fingers with ratchet-teeth and pawls, as set forth, and in combination therewith, a thumb pivotally attached to said hand and formed with a strengthening-boss that is seated in a mortise in said hand, substantially as specified.

3. In an artificial hand, a series of hinged fingers with ratchet-teeth, a corresponding series of pawls engaging said teeth, and means, as set forth, for raising said pawls, the said fingers being rigid from the hinge-joint outward and partly closed, as and for the purpose specified.

I. In combination with an artificial hand, a shank pivoted therein and arranged to yield laterally under pressure and a spring, substantially as described, for holding said shank normally in alignment with the hand.

In an artificial hand, a series of hinged fingers with ratchet-teeth, a corresponding series of pawls engaging said teeth, and a fork or similar tool clamped to one of said fingers by a spring-ferrule, as described.

SAMUEL ILL-"OAS.

\Vitnesses;

WILLARD A. LUcAs, FRANK II. ALLEN. 

